1. Field of the Invention
The present invention relates generally to power saws, and more particularly to a portable electric circular saw having a mechanism for tilting a base relative to a saw body including a rotating round blade.
2. Description of the Prior Art
Conventional portable electric circular saws include, as shown in FIG. 8, a rotating round blade 1 driven by an electric motor received in a housing or body 2, a blade guard 3 integral with the body 2 and covering an upper part of the blade 1, and a base 4 operatively connected with the body 2 and movable in a direction parallel to the plane of the blade 1 for adjusting the depth of cutting of the blade 1. The base 4 is also tiltable relative to the plane of the blade 1. A side handle or knob 5 for being gripped by the user's hand is fastened to the body 2 through an upstanding base attachment portion 6 integral with the base 4. When the cutting depth of the blade 1 is to be changed, the side knob 5 is loosened to allow the base 4 to move vertically in a position, for example, indicated by broken lines. Thereafter, the side knob 5 is tightly fastened to lock the base 4 in position against displacement relative to the body 2. A bevel plate 7 is disposed in front of the base attachment portion 6 and relatively movably connected to the same by means of a threaded fastener 8 extending through an arcuate guide groove 9 in the bevel plate 7.
In order to provide a large range of adjustment of the cutting depth, the side knob 5 is disposed closely to the body 2 and the blade guard 3, as shown in FIG. 9. During cutting operation, the circular saw is held by the user's hands at two points B and C. Since the holding point B, namely the side knob 5, is located downstream of a cutting point A in the direction of cutting indicated by the arrow, a stable holding of the circular saw is difficult to obtain. With this unstable holding, a great muscle effort is needed to prevent snaking of the cutting line. When the blade 1 is tilted relative to the base 4, as shown in FIG. 10, the side knob 5 is displaced toward the upper left of the bevel plate 7 and hence is separated far from a guide surface of the base 4. With this location of the side knob, the circular saw is held unstably and, therefore, accurate cutting is difficult to attain.